"John.Cowan" <xxxxxx@reutershealth.com> writes:

> Thomas Bushnell BSG scripsit:
>
>> > Can you live with 2^24?
>>
>> No.  Have you heard of sparse arrays?  They need indices too.
>
> Sparse arrays are not a fundamental R[56]RS type like strings and vectors.
> The question is whether these native types need to be Really Really Big.

Huh?  Sparse arrays are an *implementation* not a datatype.